Facial onset sensory and motor neuronopathy is characterized initially by paraesthesia and numbness in the region of the trigeminal nerve distribution, which later progresses to involve the scalp, neck, upper trunk and upper limbs. Onset of motor manifestations occurs later with cramps, fasciculations, dysphagia, dysarthria, muscle weakness and atrophy. This syndrome has been described in four males and appears to be a slowly progressive neurodegenerative disease. The disease is Monarch Disease Ontology identifier MONDO_0019405 (facial onset sensory and motor neuronopathy). Also known as: FOSMN syndrome.